Table 2.
Pre-ECMO characteristics, ventilator/ECMO settings, and outcomes
| All patients (n = 25) | Prone ECMO (n = 14) | Supine ECMO (n = 11) | P value | |
|---|---|---|---|---|
| Age (years) | 59 (49.5–63) | 59 (48–63) | 57 (48–66) | 0.82 |
| Male sex, n (%) | 22 (88) | 12 (85.7) | 10 (90.9) | 1 |
| Body mass index (kg/m2) | 32 (28.4–37.5) | 31.5 (28–38) | 33.6 (28.4–37.6) | 0.86 |
| Comorbidities | ||||
| Any, n (%) | 6 (24) | 3 (21.4) | 3 (27.3) | 1 |
| Hypertension, n (%) | 12 (48) | 6 (42.8) | 6 (54.5) | 0.7 |
| Diabetes, n (%) | 10 (40) | 5 (35.7) | 5 (45.4) | 0.7 |
| SAPS II | 60 (40–65) | 59.5 (46–62) | 61 (38–80) | 0.39 |
| Delay symptoms-ECMO (days) | 16 (11–18) | 15 (11–20) | 16 (10–16) | 0.94 |
| Delay mechanical ventilation-ECMO (days) | 7 (4–10) | 6.5 (4–10) | 7 (4–13) | 0.99 |
| Chest imaging (X-rays or CT) | ||||
| Consolidation, n (%) | 14 (56%) | 11 (78.6) | 3 (27.3) | 0.02 |
| Ground glass opacity, n (%) | 25 (100) | 14 (100) | 11 (100) | – |
| Bilateral infiltration, n (%) | 25 (100) | 14 (100) | 11 (100) | – |
| PaO2/FiO2 ratio before ECMO (mmHg) | 84 (69–98) | 84 (67–96) | 87 (66–102) | 0.77 |
| Prone position before ECMO, n (%) | 25 (100) | 14 (100) | 11 (100) | – |
| Neuromuscular blockers, n (%) | 25 (100) | 14 (100) | 11 (100) | – |
| iNO before ECMO, n (%) | 21 (84) | 12 (85.7) | 9 (81.8) | 1 |
| Corticosteroids, n (%) | 4 (16) | 1 (7.1) | 3 (27.3) | 0.29 |
| MV and ECMO settings the first day of ECMO | ||||
| Tidal volume (mL/kg) | 2.6 (1.9–2.9) | 2.4 (1.7–3.1) | 2.6 (2.1–2.8) | 0.71 |
| Plateau airway pressure (cmH2O) | 26 (23–29) | 26 (25–29) | 26 (21–29) | 0.52 |
| PEEP (cmH2O) | 14 (11–20) | 14 (12–20) | 14 (10–20) | 0.47 |
| Driving pressure (cmH2O) | 10 (9–13) | 11 (10–14) | 9 (8–12) | 0.44 |
| Respiratory rate (cycles/min) | 14 (12–18) | 18 (13–25) | 12 (12–14) | 0.006 |
| Respiratory system compliance (mL/cmH2O) | 25 (15–32) | 24 (14–30) | 28 (18–33) | 0.36 |
| Inspired fraction of oxygen (%) | 50 (50–80) | 55 (50–72.5) | 50 (40–80) | 0.53 |
| ECMO blood flow (L/min) | 5.9 (5–6.3) | 5.8 (5.2–6.7) | 5.9 (4.9–6) | 0.31 |
| Sweep gas flow (L/min) | 5 (4–6) | 5.5 (4.5–6.2) | 4 (3.5–5) | 0.04 |
| Membrane lung fraction of oxygen (%) | 100 (80–100) | 100 (80–100) | 100 (90–100) | 0.38 |
| Outcomes | ||||
| ECMO weaning, n (%) | 11 (44) | 3 (21.4) | 8 (72.7) | 0.02 |
| ECMO duration (days) | 10 (5–13) | 11 (6–13) | 6 (3–12) | 0.28 |
| 28-day mortality, n (%) | 14 (56) | 11 (78.6) | 3 (27.3) | 0.02 |
| Discharged alive from ICU, n (%) | 10 (40) | 2 (14.3) | 8 (72.7) | 0.005 |
| Still in ICU, n (%) | 1 (4) | 1 (7.1) | 0 | 1 |
Data are expressed as number (%) or median [IQR]. Analyses were performed with the GraphPad Prism 6 software (San Diego, CA). All tests were two-tailed, with α level at 0.05. To compare the prone ECMO group to the supine ECMO group, we used the non-parametric Mann-Whitney test for continuous variables and the exact Fisher test for categorical ones
SAPS II Simplified Acute Physiology Score, IQR interquartile range, CT computed tomography, PaO2 arterial partial pressure of oxygen, FiO2 fraction of inspired oxygen, PEEP positive end-expiratory pressure, ECMO extracorporeal membrane oxygenation, ICU intensive care unit